Processor membership in asynchronous distributed systems

Presents protocols for determining processor membership in asynchronous distributed systems that are subject to processor and communication faults. These protocols depend on the placement of a total order on broadcast messages. The types of systems for which each of these protocols is applicable are characterized by the properties of the communication mechanisms and by the availability of stable storage. In the absence of stable storage or of a mechanism for distinguishing promptly delivered messages, the authors show that no membership protocol can exist. They also discuss their experience in implementing these membership protocols     

Performance in a complex task and breathing under odor exposure

We investigated the influences of odor exposure on performance and on breathing measures. The task was composed of tracking, short-term memory, and peripheral reaction parts. During rest or while performing the task, 12 participants were exposed to 4 different odors in 2 intensities. The higher intensity of the malodors induced a short-term decrement in mean inspiration flow (Vi/Ti) after stimulus onset and impaired performance in the short-term memory task, as compared with control trials; no effect was found for the positively judged odors. The study suggests that a distractor as simple as a bad smell may pull a person off task, however briefly, and may result in a detriment to performance. Actual or potential applications of this research involve designing or securing tasks in such a way that a brief withdrawal of attention does not have fatal consequences.     

Magnebike: A magnetic wheeled robot with high mobility for inspecting complex‐shaped structures

This paper describes the Magnebike robot, a compact robot with two magnetic wheels in a motorbike arrangement, which is intended for inspecting the inner casing of ferromagnetic pipes with complex‐shaped structures. The locomotion concept is based on an adapted magnetic wheel unit integrating two lateral lever arms. These arms allow for slight lifting off the wheel in order to locally decrease the magnetic attraction force when passing concave edges, as well as laterally stabilizing the wheel unit. The robot has the main advantage of being compact (180 × 130 × 220 mm) and mechanically simple: it features only five active degrees of freedom (two driven wheels each equipped with an active lifter stabilizer and one steering unit). The paper presents in detail design and implementation issues that are specific to magnetic wheeled robots. Low‐level control functionalities are addressed because they are necessary to control the active system. The paper also focuses on characterizing and analyzing the implemented robot. The high mobility is shown through experimental results: the robot not only can climb vertical walls and follow circumferential paths inside pipe structures but it is also able to pass complex combinations of 90‐deg convex and concave ferromagnetic obstacles with almost any inclination regarding gravity. It requires only limited space to maneuver because turning on the spot around the rear wheel is possible. This high mobility enables the robot to access any location in the specified environment. Finally the paper analyzes the maximum payload for different types of environment complexities because this is a key feature for climbing robots and provides a security factor about the risk of falling and slipping. © 2009 Wiley Periodicals, Inc.     

Static analysis and process model transformation for an advanced business process to Petri net mapping

Verification of business processes typically relies on Petri net–based process models. While they allow for natural modeling and analysis of aspects such as parallelism and message exchange, such a process model is seldom complete and precise. This is mainly because the available techniques for deriving a Petri net model from the original model neglect process data in favor of feasible verification. In this paper, we present an approach for deriving more precise process models by leveraging a process‐to‐Petri‐net compiler, which takes as input a business process and generates as output a Petri net model for the process. This can be subsequently used for verification. However, in contrast to a conventional compiler, our compiler's objective is not to create the most efficient code but rather to produce a most precise but still effectively verifiable Petri net–based process model.     

A Reservation-Based Extended Transaction Protocol

With the advent of the new generation of Internet-based technology, in particular, web services, the automation of business activities that are distributed across multiple enterprises becomes possible. Business activities are different from traditional transactions in that they are typically asynchronous, loosely coupled, and long running. Therefore, extended transaction protocols are needed to coordinate business activities that span multiple enterprises. Existing extended transaction protocols typically rely on compensating transactions to handle exceptional conditions. In this paper, we identify a number of issues with compensation-based extended transaction protocols and describe a reservation-based extended transaction protocol that addresses those issues. Moreover, we define a set of properties, analogous to the ACID properties of traditional transactions that are more appropriate for business activities that span multiple enterprises. In addition, we compare our reservation protocol with other extended transaction protocols for coordinating business activities and present performance analyses and results.     

Fixed-Parameter Algorithms for Cluster Vertex Deletion

We initiate the first systematic study of the NP-hard Cluster Vertex Deletion (CVD) problem (unweighted and weighted) in terms of fixed-parameter algorithmics. In the unweighted case, one searches for a minimum number of vertex deletions to transform a graph into a collection of disjoint cliques. The parameter is the number of vertex deletions. We present efficient fixed-parameter algorithms for CVD applying the fairly new iterative compression technique. Moreover, we study the variant of CVD where the maximum number of cliques to be generated is prespecified. Here, we exploit connections to fixed-parameter algorithms for (weighted) Vertex Cover.     

Integrated optical pH sensor using replicated chirped grating coupler sensor chips

Integrated optical sensor chips suitable for high-resolution pH measurements are presented. The pH-sensitive swelling of a polymer membrane is detected by refractometry using a compact multi-channel sensor module. The signal transduction is achieved by means of chirped grating couplers which allow simple yet high functionality sensor modules to be built. The experiments have been performed with high sensitivity replicated polycarbonate TiO₂ waveguide sensor chips coated with an ultrathin photopatterned hydrogel membrane having functional groups which reversibly change from the neutral state to a charged state upon acidification. A resolution δpH <±1.1×10⁻⁴ in terms of the pH (at pH 7.5) has been obtained in a dual-channel module with size 10×10×10 cm³.     

Combined BS and MS Degree Program in Architectural Engineering

This paper describes the implementation of a combined bachelor of science and master of science degree program in architectural engineering at Kansas State University (KSU). The BS degree in architectural engineering at KSU is a five-year, 162-credit program. Students accepted into the combined BS∕MS program have the potential to reduce their undergraduate program by 15 complementary and free electives and then complete a 30-credit MS program. Availability of the program has contributed to a significant increase in the number and quality of graduate students with the potential to make a significant contribution in the building industry.     

The growing public health concern of sports concussion: The new psychology practice frontier.

With youth participation in sports at an all-time high, youths have become more vulnerable to the silent epidemic of concussion. Psychologists should become aware of the alarming frequency of mild concussion and the subtle effects of concussion, which often go unnoticed or result in misdiagnosis. This article provides a basic survey of the research and literature on this topic, a simplified knowledge base for understanding updated assessment and management techniques, and a discussion of the important role psychologists can play in educating the public and their patients. Practitioners can become more aware of this developing practice opportunity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Real-time scheduling for energy harvesting sensor nodes

Energy harvesting has recently emerged as a feasible option to increase the operating time of sensor networks. If each node of the network, however, is powered by a fluctuating energy source, common power management solutions have to be reconceived. This holds in particular if real-time responsiveness of a given application has to be guaranteed. Task scheduling at the single nodes should account for the properties of the energy source, capacity of the energy storage as well as deadlines of the single tasks. We show that conventional scheduling algorithms (like e.g. EDF) are not suitable for this scenario. Based on this motivation, we have constructed optimal scheduling algorithms that jointly handle constraints from both energy and time domain. Further we present an admittance test that decides for arbitrary task sets, whether they can be scheduled without deadline violations. To this end, we introduce the concept of energy variability characterization curves (EVCC) which nicely captures the dynamics of various energy sources. Simulation results show that our algorithms allow significant reductions of the battery size compared to Earliest Deadline First scheduling.